Conventional sensor devices have been used to measure environmental conditions. For example, via signal information generated by a conventional pressure sensor device, it is possible to monitor and electrically convey pressure conditions to a remote location over a wired link. An example of a pressure sensor assembly is shown in U.S. Pat. No. 4,875,135 granted to Bishop. In certain cases, conventional sensor devices include both a temperature sensor and a pressure sensor to measure both a temperature and a pressure of a respective environment. Examples of combination pressure/temperature sensor assemblies are shown in U.S. Pat. No. 5,974,893, U.S. Pat. No. 7,000,478, U.S. Pat. No. 7,762,140, U.S. Pat. No. 4,716,492, U.S. Pat. No. 7,434,470 and U.S. Patent Publication No. 2010/0002745A1.
One type of conventional pressure/temperature sensor assembly includes multiple components. For example, a conventional pressure sensor assembly can include a metal base component including threads in order to mount the pressure sensor assembly to a host device such as an engine block. The metal base component of the pressure sensor assembly can include a cup or hollowed region in which to house respective pressure/temperature sensor electronics, temperature sensor element, and a pressure sensor element.
The sensor electronics in the pressure sensor assembly can be configured to receive a signal from the pressure sensor element (e.g., a capacitive sense element, resistive sense element, etc.) and/or temperature sensor element (e.g., a thermistor, therocouple, etc.). The sensor elements detect an environmental condition and convey appropriate electrical signals to the electronic circuitry in the sensor assembly. The signals transmitted from the sensor elements to the pressure sensor electronics varies depending on the sensed environmental condition of the fluid.
In addition to the metal base component, a typical sensor assembly can further include a connector component electrically coupled to the pressure sensor electronics. Typically, at least a portion of the connector component can be fitted into the cup region of the pressure sensor assembly to hold and further protect the pressure sensor electronics in the cup from harmful environmental elements. A portion of the connector assembly opposite the portion in the cup can be exposed outside the cup to accept an end of a wire on which to convey the pressure information to a remote location. In certain cases, a portion of the base component is crimped to secure the connector to the base component of the sensor device. The end of the connector that is crimped to the base component retains a pressure sensor element and respective processing circuitry within the cup.
Subsequent to processing signals received from the pressure sensor element and the temperature sensor element, the electronics typically produces one or more output signals that are transmitted through the connector of the pressure sensor assembly to a remote location.
As mentioned above, conventional sensor assemblies have been configured to include both a pressure sensor element to sense pressure and a temperature sensor element to sense temperature of a fluid. However, such conventional devices are typically expensive to manufacture, are large in size, and are subject to damage.
For example, one conventional sensor assembly includes a circular ceramic pressure sensor element and a temperature sensor element. In such an assembly, respective leads of the temperature sensor element pass though a hole bored in the circular pressure sensor element. Circular pressure sensor elements are expensive and difficult to manufacture. Forming a hole in the circular pressure sensor element can be costly as it requires rather precise hole location.
Another conventional sensor assembly includes a temperature sensor element and respective leads that are effectively coated with plastic via one or more injection molding processes. In such an embodiment, when assembled in a pressure/temperature sensor device, the plastic coated temperature sensor element extends beyond a port of the sensor assembly that receives a fluid for monitoring. A drawback of such a design is that the plastic coating on the temperature sensor element does not provide a high degree of protection against damage. For example, when the sensor assembly including the plastic coated temperature sensor element is dropped from a height of one meter, the plastic coated temperature sensor element can easily crack. If the sensor assembly is then used in an intended application to monitor pressure/temperature of a caustic fluid, the temperature sensor element would be exposed to the fluid causing damage.
One way to make the conventional sensor assembly more robust is to produce an injection mold of the temperature sensor element with a thicker coating. This may increase its strength; however, the sensor assembly becomes very large in size.
Additionally, depending on the application, it may be desirable to change a length at which the temperature sensor element extends beyond the port of the sensor assembly that receives the fluid for monitoring. Use of an injection molding processor to create a coating to protect the temperature sensor element is undesirable because any adjustments to the length will require a new injection mold. This is undesirable as injection molds are expensive.